Making available Factor VII concentrates and Factor IX concentrates which are free from other proteins with clotting activities would be extremely beneficial for patients deficient in both Factor VII and Factor IX (B hemophiliacs). In fact, these two categories of illness are currently treated by using concentrates of plasmatic proteins of a prothrombin complex (also known as PPSB) containing four clotting proteins, namely Factors II, VII, IX and X. Subjected during their haemorrhage episodes to treatment by PPSB, patients deficient in Factor VII and those deficient in Factor IX receive large doses of other clotting factors (Factors II and X) whereas, prior to treatment, they have normal levels. This excess of clotting proteins may induce a risk of thrombosis. This danger is more likely with those patients deficient in Factor VII, as in vivo this protein has a relatively short half-life (7 to 9 hours) which, in order to reestablish normal physiological levels, involves injecting massive doses of PPSB and thus of Factors II, IX and X. This phenomenon is amplified by the fact that PPSB is usually poor in Factor VII (10 to 18 IU/ml as compared with 30 to 45 IU/ml of Factor X, for example). Treatments with total plasma have been proposed, but these induce well-known risks of vital contamination as the therapeutic plasma is usually not inactivated with regard to pathogenic viruses. These treatments also require the same massive and repeated injections as with PPSB and results in a build up of accessory plasma-derived proteins.
Although there are certain publications demonstrating the usefulness of ion exchange (DEAE) chromatography and affinity chromatography (heparin-Sepharose) (Andersson et al., Thrombosis Research; 7, 451-459, 1975), there are few specific therapeutic Factor VII and Factor IX concentrates. There currently exists a Factor VII concentrate, but this derivative contains antigens of Factors IX, II and X, protein C and large doses of heparin. A method for preparing a high-purity Factor IX concentrate has been published (Menache et al., Blood, 64, 1220-1227, 1984); however this method uses two chromatographic adsorption steps. The first step is batch processing in the presence of DEAE-Sephadex, and the second step is a passage through a column of dextran sulfate gel. This technique consists of purifying PPSB (DEAE-Sephadex) and then isolating Factor IX by virtue of its affinity for dextran sulfate. However, this method does not offer all the advantages of industrial column chromatography due to the batch adsorption step (a method that can only be slightly automated and which is poorly reproducible) and impairs the optimized recovery of other potentially useful plasmatic fractions. Finally, it does not favor the simultaneous recovery of proconvertin.